As requirements for mobile communications services increase, requirements for network bandwidth increase exponentially. Microwave transmission is an important means of mobile backhaul and has an increasingly high requirement for bandwidth. Microwave spectrum resources are limited, and it becomes particularly important to improve utilization of a microwave spectrum. In an existing full duplex (FD, Full Duplex) technology, signals are transmitted and received simultaneously at one frequency over an air interface. As compared with two conventional duplex modes, that is, frequency division duplex (Frequency Division Duplex, FDD) and time division duplex (Time Division Duplex, TDD), full duplex improves spectrum utilization of a system.
When a full duplex technology is applied in microwave communication, two extreme cases exist: When weather conditions are good, the atmosphere causes little signal attenuation, wanted signals received by a system are much more than self-interference signals, and a capacity of the system can be further increased by means of full duplex communication. When weather conditions are bad, the atmosphere causes large signal attenuation, wanted signals received by a system are much less than self-interference signals, and if the system still performs communication in a full duplex mode in this case, quality of the communication is seriously affected, and a capacity of the system is reduced.